Washington — The Senate on Monday failed for the second time to clear a key procedural hurdle to advance a massive legislative package designed to provide economic relief to American workers and industries battered by the coronavirus outbreak, as tensions boiled over among senators who vocalized their frustrations with one another over negotiations.

Senate Democrats blocked the yet-to-be-finalized stimulus package from advancing in a vote of 49 to 46, denying Republicans the 60 votes needed to move forward. Monday's action was yet another setback for senators following a failed party-line procedural vote Sunday.

Senate Majority Leader Mitch McConnell warned it could be several days before the Senate can proceed to a vote on the deal and called the failed procedural vote "mindless obstruction."

The failure followed tense and heated exchanges on the Senate floor, with Republicans accusing Democrats of exploiting a crisis while time runs out to pull the economy back from the brink.

"The country is burning, and your side wants to play political games," Republican Senator John Thune of South Dakota said. "It's time to get this done. The American people expect us to act."

McConnell urged the Senate to act with urgency as more states place stringent limitations on residents to limit the spread of the coronavirus, including by ordering businesses deemed nonessential to close.

"This is not a juicy political opportunity. This is a national emergency," McConnell said during remarks on the Senate floor before the votes.

McConnell accused Democrats of making 11th-hour demands that derailed progress on the package, including tax credits for solar energy and wind energy and new emissions standards for airlines, which are set to benefit from the stimulus package.

"Are you kidding me?" the Kentucky Republican said, adding that Democrats decided their requests are "more important than Americans' paychecks and the personal safety of doctors and nurses."

McConnell continued to place blame on House Speaker Nancy Pelosi, who joined discussions over the legislative package Sunday morning.

"The speaker of the House flew back from San Francisco, and suddenly, the Senate's serious bipartisan process turned into this left-wing episode of 'Supermarket Sweep,' unrelated issues left and right," he said.

McConnell urged Democrats to unify with their Republican colleagues, warning the country "doesn't have time for these political games."

Senate Minority Leader Chuck Schumer, taking to the Senate floor after McConnell, cast a grim outlook for the second procedural vote, calling it "irrelevant" and saying negotiations are ongoing, just steps from the Senate chamber.

"Democrats will not stop working with our Republican counterparts until we get the job done," he said.

GOP senators descended to the floor of the chamber to express their outrage over the hold-up and accused Democrats of delaying aid as families continue to hurt.

Senator Susan Collins, a Republican from Maine, angrily denounced her Democratic colleagues for not agreeing to move forward.

"I cannot believe that the answer from our friends from the other side of the aisle is delay, delay, delay. No sense of urgency," she said. "We don't have another day. We don't have another hour. We don't have another minute to delay acting."

Republican Senator John Kennedy of Louisiana said Americans are thinking that "this country was founded by geniuses, but is being run by a bunch of idiots."

"You know what the American people are thinking right now? They're thinking that the brain is an amazing organ — it starts working in a mother's womb and it doesn't stop working until you get elected to Congress," he said.

Discussions on the nearly $2 trillion stimulus package — likely to be the largest in history — continued into Sunday night and the morning, and Schumer told reporters the goal was to craft a bipartisan compromise on Monday. Treasury Secretary Steven Mnuchin and Eric Ueland, the White House legislative affairs director, met with Schumer at the Capitol in the morning.

It's unclear when a vote on final passage of the measure could take place, but McConnell had been pushing for the Senate to approve the stimulus package as early as Monday. The first two of three procedural votes set for Monday required 50 votes to pass, and the third vote required 60.

Further complicating negotiations was the announcement from Pelosi that she plans to introduce her own stimulus package Monday afternoon.

"The Senate Republicans' bill, as presented, put corporations first, not workers and families," Pelosi said in a statement. "Today, House Democrats will unveil a bill that takes responsibility for the health, wages and well-being of America's workers: the Take Responsibility for Workers and Families Act."

In the run-up to Sunday's failed procedural vote, Republican senators had expressed optimism about a bipartisan compromise, which includes cash payments of $1,200 to American workers making up to $75,000; $350 billion in loans and grants for small businesses; and $50 billion in loans for airlines.

But Democrats said the package lacked adequate funding for hospitals and health care workers and gave too much money to large corporations without oversight. All 47 Senate Democrats voted together in blocking the measure from advancing Sunday.

The failed vote incensed Senate Republicans, some of which took to the Senate floor to express their frustration.

Immediately following the vote, a visibly angry McConnell blamed Pelosi for upending progress on the deal and urged Democrats to "step up" to help American workers and businesses.

"We're fiddling here, fiddling with the emotions of the American people, fiddling with the markets, fiddling with our healthcare, the American people expect us to act tomorrow," McConnell said Sunday. "And I want everybody to fully understand if we aren't able to act tomorrow, it'll be because of our colleagues on the other side continuing to dicker when the country expects us to come together and address this problem."

Adding to the uncertainty on Capitol Hill was the revelation that Senator Rand Paul of Kentucky had tested positive for the coronavirus and would be self-quarantining.

The announcement led two other GOP senators, Mike Lee and Mitt Romney, both of Utah, to self-quarantine after coming into contact with Paul. Senators Cory Gardner and Rick Scott of Florida were already self-quarantining after possible exposure to the virus, meaning five senators in total had to miss Sunday's vote.

The stimulus package under discussion in the Senate is the third part of a multi-pronged legislative response to the coronavirus. Earlier this month, Congress passed a $8.3 billion emergency supplemental package, and last week, President Trump signed into law a coronavirus relief bill that provides free testing and paid leave for certain workers.